Conventional box stitching machines include a stitching head mounted on a bridge frame for applying wire stitches to overlapping portions of a box blank passing therebeneath, and conveying means for advancing the box blank passed the stitching head. Box manufacturers employ such wire stitching apparatus in stitching boxes designed to hold extremely heavy contents.
One of the basic requirements of box stitching machines is that the stiches be applied at precisely desired locations, for example, with respect to the leading and trailing folds which define the intermediate body portion of the planar box blank. This requirement is, in part, satisfied by carefully controlling the path of the box blank passing beneath the stitching head. However, it is also necessary to accurately position the stitching head on the bridge frame vis-a-vis the path of travel of the box blank passing therebeneath. This may be accomplished automatically through the use of complex costly automatic electro-mechanical means.
Manual positioning of the stitching head on the bridge frame has been attempted with only moderate success. It has been suggested to employ rollers between the stitching head and bridge frame to achieve smooth and manual lateral movement of the stitching head. Unfortunately, it has been found that rollers cannot withstand the high shockloads imparted on them as the head goes through the stitching function. With no other feasible alternative available, the art has turned to the use of sliding pads to effect manual movement of the head. However, the sliding pads tend to wear quickly and do not provide for the desired smooth lateral movement.